Miller County, as created by an act of the Territorial Legislature of Arkansas on April 1, 1820, included most of what is now Miller County, Arkansas, and the Texas counties of Bowie, Red River, Lamar, Fannin, Cass, Morris, Titus, Franklin, Hopkins, Delta, and Hunt. The area, named for James Miller, territorial governor of Arkansas, was partially taken out of Hempstead County, where Stephen F. Austin had held court in 1820. The original county seat was in the John Hall house in the Gilliland settlement. In 1831 a five-man commission located the county seat at the Jonesborough plantation near what is now Clarksville, Texas.

In 1836 Texas became a republic and Arkansas became a state. Most of the residents of the county considered themselves Texans; Travis G. Wright, Richard Ellis, and Bailey Inglish were significant figures in the Republic of Texas. For a time the territory was represented in both the Arkansas Legislature and the Texas Congress. In 1837 Texas organized Red River County; Arkansas retaliated in 1838 by making it a misdemeanor for a citizen in the county to hold an office in the Republic. Texas then created and organized Fannin County in 1838. Arkansas failed in an attempt to establish a county court and attach the area to Lafayette County. Annexation of Texas to the United States in 1845 settled the approximate boundary between Texas and Arkansas. In December 1874 Miller County was created out of that part of Lafayette County lying west and south of the Red River, and Texarkana, Arkansas, was made the county seat.

BIBLIOGRAPHY: W. H. Arnold, "Historical Sketch Relating to Establishment of State Line between Arkansas and Texas and Relating to the Creation of the Old and New Miller County, Arkansas," Arkansas Historical Quarterly 5 (Summer 1946). W. H. Arnold, "Historical Statement of Texarkana, Arkansas, to February 7, 1917," Arkansas Historical Quarterly 5 (Winter 1946). Barbara Overton Chandler and J. E. Howe, History of Texarkana and Bowie and Miller Counties, Texas-Arkansas (Texarkana, Texas-Arkansas, 1939).

Seymour V. Connor